This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The dynamics of the particles of nano-scaled (~50nm) in the living system was hard to observed. That was due to the limitation of the wavelength used in the detection instruments. By applying the circular scan algorithm and the multi-photon excitation microscopy, we were able to measure the the moving particle trajectories in real time, providing important information such as the chromatin dynamics during interphase. Besides the trajectories, the next step we would like to move forward to observe the orientation and shape changes of the moving particles. This provides further message about how the particles interact and more detailed dynamic information in the living system.